This invention relates to a fuel conditioner assembly for use in a liquid fuel handling system between a supply of liquid fuel and a point of utilization where the fuel is atomized and combusted to provide power for a heat engine, more particularly in a liquid fuel circuit between a supply tank containing liquid fuel, and one or more injectors where the fuel is atomized. The fuel conditioner performs liquid fuel heating and pressure regulation functions.
The basic idea of using an electric heater to heat fuel prior to delivery for combustion is illustrated in U.S. Pat. No. 1,350,871. U.S. Pat. No. 2,599,699 discloses a fuel system in which the recirculation of liquid fuel in the fuel circuit is thermostatically controlled by a mixing valve such that during warm-up, return fuel from the injectors is recirculated to the injectors by-passing the tank, and after warm-up, the return fuel from the injectors is recirculated through the tank. U.S. Pat. No. 2,988,075 shows a fuel heater containing a thermostatically controlled valve, and an associated pressure regulator combined with the valve. Thus, the general elements of an electric heater, a thermostatically controlled valve, and a pressure regulator are known in fuel handling systems where fuel is delivered from a supply tank to a device which atomizes the fuel.
The following additional U.S. patents were also developed in a preliminary search conducted with respect to the fuel conditioner assembly of the present invention:
______________________________________ 3,768,730 4,231,342 4,386,584 3,779,007 4,359,972 4,440,138 4,056,086 4,372,260 4,452,213 4,187,813 4,377,149 4,454,851 4,228,776 4,385,615 ______________________________________
The present invention relates to a fuel conditioner assembly in which the fuel heating and pressure regulation functions are performed by a new and unique organization and arrangement of various parts. The invention provides a compactness to the overall size of the assembly and enables the assembly to be fabricated and to perform in an efficient manner.
The fuel conditioner assembly of the invention comprises, in its preferred embodiment, a generally rectangular body having two parallel bores arranged side by side. An electrically powered heater is disposed in one bore. The second bore is divided by a transverse wall which has a central hole. A thermal motor actuator is disposed in this second bore on one side of the transverse wall, and a spring-biased valve is disposed in the same bore on the opposite side of the transverse wall. The thermal motor actuator operates the spring-biased valve via a tubular element which passes through the hole in the transverse wall. Fuel from the tank enters the assembly via an inlet port at an entrance to the portion of the second bore which contains the thermal motor actuator. The fuel passes across the thermal motor actuator and exits the second bore through a slant passage to enter the first bore. The fuel flows through the first bore, passing along the heater to an outlet port where the fuel exits the assembly for passage to the injector. Return fuel from the injector enters the assembly at a return port immediately adjacent which a pressure regulator is disposed for pressure regulation action on the returning fuel just after the fuel enters the assembly. From the pressure regulator, the fuel moves through a skewed passage which extends to an entrance to that portion of the second bore which contains the spring-biased valve. The thermal motor actuator senses the temperature of liquid fuel which passes through that portion of the second bore within which the thermal motor actuator is disposed, and it exercises control over the spring-biased valve in accordance with the sensed fuel temperature. The spring-biased valve is biased by the spring to a position which results in essentially the entire return flow passing through a central hole in the valve and through the tubular element back to that portion of the second bore which contains the thermal motor actuator. When the thermal motor actuator senses only relatively cold fuel, it does not displace the valve from the postion to which the valve is spring-biased. As the temperature of the fuel passing across the thermal motor actuator becomes relatively warmer, the thermal motor actuator acts via the tubular element on the spring-biased valve in a manner which displaces the valve against the spring force. This causes a decreasing proportion of the return fuel entering the portion of the second bore which contains the valve to recirculate to the portion of the second bore which contains the thermal motor actuator, and correspondingly an increasing proportion to recirculate to the tank via a tank port which leads from that portion of the second bore which contains the valve. At the extent of maximum valve actuation by the thermal motor actuator, essentially all return fuel recirculates to the tank instead of to the portion of the second bore which contains the thermal motor actuator. The body of the assembly comprises a face containing a wall which is upright relative to that face and surrounds a region of that face. The pressure regulator mounts on the body in a sealed manner against the upright wall. The return port extends through the upright wall. The pressure regulator has a mechanism which acts in a direction normal to that region of the face bounded by the upright wall in coaction with a hole in the region leading to the previously mentioned skewed passage.
The foregoing features, advantages, and benefits of the invention, along with additional ones, will be seen in the ensuing description and claims, which should be considered along with the accompanying drawings. The drawings illustrate a preferred embodiment of the invention according to the best mode contemplated at this time for carrying out the invention.